Gaseous fuel burner for furnace walls



Oct. 16, 1951 R. E. BUCKHOLDT GASEOUS FUEL BURNER FOR FURNACE WALLSFiled Oct. 2 1946 ROBERT E. BUCK OLDT- M iwgww Patented Oct. 16, 1951OFFICE GASEOUS FUEL BURNER FOR FURNACE WALLS Robert E. Buckholdt, Salem,Ohio, assignorto The Salem Engineering Company, Salem, Ohio,

a proprietorship Application October 2, 1946, Serial No. 700,783

This invention relates to gaseous fuel burners, and has among itsprincipal objects the provision of a burner of the gas and air mixingtype which is of materially simplified and dependable construction butwhich nevertheless has improved performance characteristics as regardsthe volume of supplied combustion air and as regards the thoroughintermixing of the gaseous fuel and air.

A further object of the invention is the provision of a gaseous fuelburner of such improved design that deposition and/or escape ofcombustible colloidal carbon particles is materially reduced.

Another and more specific object of the invention is the provision of asimple but dependable gaseous fuel burner particularly adaptable for usein a furnace wall having a diverging burner port formed of refractorymaterial and when so adapted having the improved characteristic ofeffecting sufiicient incandescence in the port lining to materiallyassist in effecting complete combustion of the gaseous fuel supplied.

The above and other objects and advantages of the invention will becomeapparent upon consideration of the following detailed specification andthe accompanying drawing wherein there is disclosed certain preferredembodimentsof the invention.

In the drawing:

Figure l is a sectional view of a refractory furnace burner port and anassembled gaseous fuel burner constructed in accordance with principlesof the invention;

Figure 2 is a sectional View generally similar to Figure l but showing amodified assembly constructed according to the teachings of theinvention;

Figure 3 is a transverse sectional view taken along the line III-III ofFigure 1;

Figures 4, 5 and 6 are detailed sectional views taken along the linesIV-IV, V--V, and VI-VI, respectively, of Figure 2; and

Figure '7 is an end view of the fuel supply tube of the assembly ofFigures 1 and 2.

Referring to the drawing in detail, there is provided concentric innerand outer tubes I II and I I, respectively, and in practice the gaseousfuel is preferably conducted into the tube Ill while air for combustionis conducted into tube I I. To facilitate manufacture and assembly allthe ports of the burner are preferably carried by the tube II and toprovide means, in turn, whereby the tube II may be readily assembled ona furnace wall, for example, the tube II may be provided 2 Claims. (Cl.1587) with an integral flange I2 which is arranged to lie against and tobe secured to the outer face I3 of the furnace wall I l. Of course, eachburner is associated with a burner port and in practice such ports willhave their walls built up of refractory material either as an integralpart of the furnace wall construction or in the form of separablepre-formed tile structures as is well understood in the art. In eitherembodiment the ports are usually circular and are of increasing crosssectional area in the direction of flame propagation as shown at I5 inFigures 1 and 2.

The inner end portion of tube II is turned radially inward, as shown, toprovide a restricted end orifice It and an inwardly tapering portion IIon the inner wall surface of the tube. The inner tube i ii is formedwith an inwardly tapered end portion I8 and a closed end which ispositioned substantially in the orifice It. It should be apparent thatthe degrees of taper of the inner wall portion ll of the tube II and ofthe outer surface portion I3 of the tube Iii are substantially equal sothat there will be provided an annular but radially inward air injectionspace which sweeps across the surface I8 substantially parallel thereto.A series of circumferentially spaced apertures I9 are formed in thetapered wall portion is of the tube I0 and the individual axes of theapertures l9 are normal to the direction of air flow across the surfaceI8.

The inner end of tube III is accurately positioned in concentricrelation in the orifice it by a spider 26 which has a ring portion 2|closely received over the tube Ill and a plurality of integralcircumferentially spaced but radially outward extending legs 22 whichare closely received in the tube I0 and which are preferably streamlinedin a direction of fluid flow in the tube I I as shown in Figure 6. Byreferring to Figures 1 and 2 it will be observed that the outer endedges of the ring portion 2i are tapered generally complementary to thetapering of surface I? so that a minimum of impedance is offered to theflow of fluid through and out of the tube I I.

In the burner assembly thus far described the orientation of the fuelejecting apertures I9 is such as to cause a diverging cone of fuel gasto issue from the inner end of the tube I0 and this cone will betraversed at substantially right angles by the converging cone ofcombustion air issuing from the tube II. There will thus be effectedthorough and intimate mixing of air and the lighter components of thegaseous fuel but some of this fuel including substantially all theheavier components thereof will be caused to move along 3 in a divergingcone. Now if the burner thus far described is associated with a taperingport having a refractory wall and having its diverging portion beginningfairly close to the orifice Hi, all as illustrated in Figures 1 and 2,it will be observed that the above mentioned diverging fuel cone willmove along and in wiping contact with the diverging surface l5 of theburner port. The diverging fuel cone is, of course, a highly combustiblemixture and progressive ignition will take place upon progression of thesame along the surface thereby effecting a high heating of the wallsurface 15. Upon the burner being in operation a short time the surfaceI5 becomes incandescent and the resultant highly increased radiationtherefrom is highly advantageous in breaking down the more complexcomponents of the gaseous fuel to insure complete combustion. Further,this high radiation has the further beneficial effect of imparting suchadditional heat to the initial products of combustion which may includefree carbon of colloidal particle size that upon subsequent expansionand further intermixing of all the gasses in the port and therefore uponthe subsequent co-mingling of the carbon and sufiicient oxygen forcombustion ignition will be sustained, thus further effecting completecombustion of the fuel.

In the embodiment of Figure 2 the radiation factor above outlined may befurther increased by positioning in the forepart of the diverging burnerport a bulbous member 23 which is preferably formed of a highlyrefractory material as sintered silicon carbide, for example, and inpractice the mass 23 may be formed on the end of a rod 24 of a highheat-resistant metal alloy. Rod 24 is rigidly carried by the inner endof tube l0 and, as shown, the principal axis of rod 24 and of thebulbous member 23 is in general continuation of the principal axis ofthe tube I0. The 4 length of rod 2-1 is determined by the throat depthof the particular burner port with which the assembly is to be used sothat the inner or conical portion of the member 23 will be generallyparallel with the inner conical portion of the burner port. If required,a protecting sleeve 25 formed either of refractory material as sinteredcarbide or of a heat-resistant alloy may be positioned about the rod 24intermediate the end of the tube II] and the inner end of the bulbousmass 23.

The burner of Figure 2 being in operation a very short time the bulb 23will reach high incandescence and the fuel and air mixture passingthrough the space intermediate the bulb 23 and the burner port surface[5 will be subjected to extremely rapid radiation heating with theconsequent beneficial results explained above in connection with theoperation of the burner of Figure 1.

It should now be apparent that I have provided improved gaseous burnersof simple and rugged construction but which effect improved results inthe completeness of combustion of the gaseous fuel furnished. Further,the herein taught correlation of the burner design with the design ofthe refractory burner port is thought to be particularly advantageous asregard the efficiency of operation of gas-fired furnaces generally.

The above specifically described embodiments of the invention should beconsidered as illustrative only as obviously many changes may be madetherein without departing from the spirit or scope of the invention.Reference should therefore be had to the appended claims in determiningthe scope of the invention.

What I claim is:

1. A gaseous fuel burner assembly comprisin in combination a refractoryfurnace wall having an inwardly diverging burner port, an air conductingtube having a restricted end discharge orifice registering with theinlet end of said port, a fuel injecting tube positioned concentricallywith said first mentioned tube and having an inwardly tapering endportion and a closed inner extremity positioned substantially in saidorifice, a plurality of circumferentially spaced apertures in thetapered portion of said gas injecting tube, a bulbous member ofincandescing material positioned in the forepart of said inwardlydiverging burner port and having a conical section spaced radiallyinward from but substantially parallel with a portion of the wall ofsaid port, and means projecting inwardly from said closed extremity ofsaid gas injecting tube to support said bulbous member.

2. A gaseous fuel burner assembly comprising in combination a furnacewall having an elongated furnace port having an inwardly diverging sidewall, an air conducting tube having an inwardly tapering inner walladjacent its discharge end mounted adjacent the inlet of said port andin alignment therewith, a fuel conducting tube concentrically disposedwithin said air conducting tube and having an inwardly tapering innerend portion disposed in parallel spaced relation with said inwardlytapering wall of said air conducting tube, said fuel conducting tubehaving a closed inner end disposed substantially in the dischargeorifice of said air conducting tube whereby a converging annular flow ofair is caused to move inwardly across the tapering portion of said fuelconducting tube, a series of circumferentially spaced apertures in thetapered portion of said inner tube for the emission of gaseous fuel, anelongated support carried centrally on the inner end of said fuelconducting tube and projecting centrally into said port, and a bulbousmember of incandescing material mounted on said support and having aconical section spaced radially inward from but substantially parallelwith a portion of the side wall of said port.

ROBERT E. BUCKHOLD'I.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,140,785 Cone Dec. 20, 19382,183,596 Trinks Dec. 19, 1939 2,286,857 Holthouse June 16, 1942 FOREIGNPATENTS Number Country Date 765 Great Britain 1877 358,234 Germany Sept.7, 1922

